Imagine the following:

• Servers declare a target number of users/posts-per-day (enables programmatically detecting when other people's servers are generally under/over capacity)
• Severs have a recommender list of other servers (whitelist), separate and more exclusive than their non-blocked list

Whenever someone goes to the sign up page, for example, on Lemmy.world, we:

• look at the recommender list
• find the server that is most under capacity
• have a very large iframe with "Sign up for Lemmy (using [under capacity server here])"
• have a small "No, I want to sign up specifically on Lemmy.world" option

AND, as a precaution against maybe-malicious takeovers (e.g. a Facebook server saying it has unlimited capacity and all new users getting forwarded to them) a server can set it's own maximum recommender caps; e.g. "recommended" servers won't be recommended if they're above 10,000 users even if they claim they could handle more.

Thoughts?